1. Field of the Invention
The present invention relates to an auto driving control system for vehicles, and, in particular, relates to an auto driving control system capable of supporting automatic traveling safely even when abnormalities occur on sensors supporting automatic traveling of a vehicle.
2. Description of the Related Art
In a conventional auto driving control system for vehicles, when automatic traveling is able to be performed, the automatic traveling is executed continuously. However, the auto driving control system is configured to, when it is determined that the automatic traveling is not able to be performed, notify an occupant of the determination result.
For example, in JP-2008-49888-A, in accordance with the determination result as to whether automatic traveling is able to be performed in terms of a distance between the vehicle and another vehicle and the like, an occupant is notified of the propriety of the automatic traveling. In concrete terms, determination conditions have been set previously for the respective determination items, such as a situation in the vicinity of two or more types of vehicles, a history of dangerous drive operations, and a traveling distance after starting automatic control. Then, ACC and an ECU determine, based on the determination conditions, whether automatic control (so-called, ACC control) can be executed in the traveling state of a vehicle (i.e., a traveling speed and a distance between the vehicle and a preceding vehicle). Successively, in the case where it has been determined that the ACC control can be executed, a message showing the determination result is displayed on a display. Furthermore, when a driver inputs a start instruction of the ACC control via an ACC switch in response to the displayed message, the vehicle is controlled to be in a prescribed traveling state.
Furthermore, according to JP-2015-32291-A, in accordance with the state of a driver, the notification level is changed. In this case, an automatic travel support device includes a support control unit 11, a support determining unit 12, a state determining unit 13, a notification control unit 15, and a notification output unit 25. Furthermore, the above units are configured as follows. The support control unit 11 controls automatic travel support for a vehicle. The support determining unit 12 determines whether the automatic travel support can be continued. The state determining unit 13 determines whether a driver of the vehicle is able to drive normally. The notification output unit 25 issues a warning with regard to the automatic travel support in accordance with the determination result of each of the support determining unit 12 and the state determining unit 13. In the case where it is determined that the automatic travel support cannot be continued and it is determined that the driver is unable to drive normally, the notification control unit 15 makes the level of warning higher than that in the case where it is determined that the automatic travel support can be continued and it is determined that the driver is unable to drive normally, or in the case where it is determined that the automatic travel support cannot be continued and it is determined that the driver is able to drive normally.
However, even in the case of performing any kind of notification, these conventional techniques assume that a driver is able to drive.
For this reason, even in the traveling with an automation level of 3 or more which is defined by Ministry of Land, Infrastructure and Transport and National Highway Traffic Safety Administration, an occupant required to keep a state of being able to drive regardless of the condition that a driver is allowed to respond only at the time of emergency at the automation level of 3 or more.
The reason is that, for example, in the case where automatic driving with an automation level of 3 or more becomes impossible due to failure of sensors or a change of the weather, in the current system, the control of a vehicle is returned to an occupant immediately.
Furthermore, similarly, also in traveling with an automation level of 2, in the case where the usual automatic traveling becomes impossible, the control of a vehicle is returned to an occupant immediately. However, since it is difficult to assume the situation recognition of the occupant without making mistakes, it is hard to say that the driving is taken over safely. For example, in the case of poor visibility under the bad weather, it may be difficult for a human to drive. There may be also a case where an occupant cannot take over driving safely due to sudden illness and the like.
Furthermore, as a countermeasure in the case where automatic traveling becomes impossible, decelerating and stopping may be considered. However, on a highway, a street intersection, a railroad crossing, or a curved road with low visibility, the control for decelerating and stopping may not be safe.
For this reason, at the time of automatic traveling, even in the case where continuation of the automatic traveling becomes difficult, it is necessary to take over the driving to an occupant with a time allowance in response to the state of the occupant.